[Flang][Driver]Add datalayout before doing LLVM-IR transformation

The earlier available datalyaout allows MLIR to LLVM-IR transformation
to use the datalayout for decisions, such as comparing sizes for
different types of integers.

This should solve https://github.com/llvm/llvm-project/issues/57230

Reviewed By: awarzynski, vzakhari

Differential Revision: https://reviews.llvm.org/D133568